(1) Field of the Invention
This invention relates to an improved ribbon cartridge for use in a printing machine, and more particularly, for use in an electronic printing calculator. Specifically, the invention relates to a ribbon cartridge having a self-contained inked ribbon therein adapted for convenient insertion into the printing machine.
(2) Description of the Prior Art
The usual construction of a calculator printing mechanism, whether electronic or manual, prevents insertion of a ribbon in a self-contained cartridge. A mechanism of the type referred to herein is comprised of an obstructing reversing member located in between gears with axles attached thereto. These gears with the axles attached are laterally spaced from each other. The gears are located in the same plane and the axles are located parallel to one another in a plane orthogonal to that of the gears. Usually, a spool with an inked ribbon is placed and stored on one of the axles and another spool for taking up the ribbon is placed and stored on the other axle. When all of the ribbon is taken up, this event is sensed or detected by the reversing member which operates laterally in a plane parallel to the gears, and the respective roles of the spools are reversed.
The ribbon travels from one of the spools in between a platen and printer to the other spool and usually must be loaded in the mechanism by hand. An operator inserting exposed spools with inked ribbon thereon into the printing mechanism routinely receives soiled hands from the ink in the ribbon. Moreover, the procedure for inserting both of the spools and threading the ribbon in between the platen and printer is often-times cumbersome and time-consuming, wasting a considerable amount of valuable operator time.
Ribbon cartridges containing spools of inked ribbon have been heretofore constructed. However, one problem with these previously constructed ribbon cartridges is that they also have been difficult and cumbersome to insert into the printing mechanism because a member for sensing the quantity of ribbon on each spool (often combined with a reversing mechanism) is located within the printing mechanism between the spools. The member may be designed to operate by resting against either the unfilled or filled spool. If it is against the unfilled spool, as the unfilled spool fills up with ribbon the lever is gradually forced toward the central region between the two axles. When the take-up spool is substantially filled the lever is forced back toward the now unfilled spool, at the same time reversing the drive mechanism such that the ribbon, instead of traveling from the first initially filled spool to the unfilled spool, is now driven from the filled spool toward the now unfilled spool. Similarly, the lever can be fashioned such that reversal of movement occurs with the lever resting against a depleted spool. The lever can be spring loaded against the filled spool so as to trigger reversal of the spool movement and then pivot to the filled spool after it comes within a predetermined range of the axle of the filled spool.
Heretofore a calculator operator desiring to change the ribbon had to use an external and separate tool or other means such as a hand for moving the reversing lever out of the way of the cartridge to be inserted. This has been a most cumbersome and tedious procedure because of the small space which the operator has available in which to manipulate fingers for moving the lever out of the way.